This invention relates to manhole covers and, more particularly, to a method and apparatus for raising and lowering manhole covers.
Prior to our invention, it was customary for one person to use a pick to wedge open or pry up one edge of the manhole cover. A second person would then grab the partially raised cover and hold it until his partner could also help him move the cover.
Some covers can weigh up to about 400 pounds and many serious injuries have resulted from this method of handling manhole covers. To the best of our knowledge, the only attempt to overcome the hazards and difficulties associated with handling manhole covers has been the use of a chain fall secured to a tripod. However, this arrangement did not provide a convenient way of pivoting the cover to a desired final position. For this reason and because it is cumbersome, the arrangement has received very little acceptance by industry.